B. G. Jefferis and J. L. Nichols, Searchlights on Health — How to Read Character (1919)
“ VULGAR LAUGH.—Vulgar persons always laugh vulgarly, and refined persons show refinement in their laugh. Those who ha, ha right out, unreservedly, have no cunning, and are open-hearted in everything; while those who suppress laughter, and try to control their countenances in it, are more or less secretive. Those who laugh with their mouths closed are non-committal; while those who throw it wide open are unguarded and unequivocal in character. ”
